1. Technical Field
The present invention relates to a terahertz wave detecting device, imaging device, and measuring device.
2. Related Art
In recent years, attention has been devoted to terahertz waves, which are electromagnetic waves with frequencies of 100 GHz or greater and 30 THz or less. Terahertz waves can be used in various forms of measurement and non-destructive testing such as imaging and spectrometry. Terahertz wave detectors for detecting terahertz waves include pyroelectric sensors, bolometers and the like. Major features of these include high sensitivity to terahertz waves and not requiring optical delay mechanisms that are large and cumbersome such as a THz-TDS (Time Domain Spectrometry) spectroscopic analysis device.
When using a pyroelectric sensor or bolometer for the THz-TDS spectroscopic analysis device, both the pyroelectric sensor and bolometer detect the existence of terahertz waves by changes in the heat volume within the components. Because of that, detection of the terahertz wave frequency spectrum is impossible, and to perform spectrum detection, it is necessary to have a wavelength filter that selectively transmits terahertz waves of the prescribed wavelengths one wishes to detect.
Currently, a wavelength filter has been proposed that transmits terahertz waves of prescribed wavelengths (see International Application Publication No. WO2008/075624, for example). This wavelength filter is constituted by a substrate and a metal film provided on the substrate which has a plurality of pores. By combining this wavelength filter and a pyroelectric sensor or bolometer, it is possible to detect only terahertz waves of prescribed wavelengths.